I've had to inject a cat and a rabbit at various times over the years. With mine it was because they wouldn't take the meds any other way - even when the vet tried and it wasn't practical to take them into the vet twice a day.
With both of them I injected at the scruff of the neck and I practiced with a syringe full of water in front of the vet. I found it much easier than trying to get tablets down these particular animals. Most of mine are fine - but not this particular bunny or cat!!!
I had to take the empty syringes back to the vet and they were counted before being disposed of.
Initially, I worried about doing it as I am one of these people who hates needles but I just told myself if one of my animals developed diabetes I may have to do it so it was as well I got over my phobia asap. I soon got the hang of it and neither animal struggled at all.
I am not sure how I would have felt about injecting in another area though - the neck had so much loose skin it was quite easy. Both animals got better so I must have done something right.
Lumps